21013312031 has 2 divisors, whose sum is σ = 21013312032. Its totient is φ = 21013312030.

The previous prime is 21013312007. The next prime is 21013312063. The reversal of 21013312031 is 13021331012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21013312031 - 2¹⁸ = 21013049887 is a prime.

It is a super-2 number, since 2×21013312031² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21013312081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506656015 + 10506656016.

It is an arithmetic number, because the mean of its divisors is an integer number (10506656016).

Almost surely, 2^21013312031 is an apocalyptic number.

21013312031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21013312031 is an equidigital number, since it uses as much as digits as its factorization.

21013312031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 17.

Adding to 21013312031 its reverse (13021331012), we get a palindrome (34034643043).

The spelling of 21013312031 in words is "twenty-one billion, thirteen million, three hundred twelve thousand, thirty-one".